Japanese Patent Application Publication No. 2011-82220 (hereinbelow referred to as Patent Literature 1) discloses an RC-IGBT (Reverse Conducting Insulated Gate Bipolar Transistor) in which a diode and an IGBT are provided in a single semiconductor substrate. An n-type cathode layer is provided in a range exposed on a lower surface of the diode. An n-type buffer layer is provided above the cathode layer. An n-type drift layer is provided above the buffer layer. An n-type impurity density of the drift layer is lower than those of the buffer layer and the cathode layer. The n-type impurity density of the buffer layer is lower than that of the cathode layer.